DE102014009856A1 - Method and device for adapting the accelerator pedal characteristic in a motor vehicle - Google Patents

Abstract

The invention relates to a method for adjusting the accelerator pedal characteristic in a motor vehicle, in which a characteristic (1) describing the relationship between the accelerator pedal position and the engine torque request of the driver is modified, wherein it is determined whether there is a situation of increased driving resistance; and in the event that there is an increased driving resistance situation, the accelerator characteristic is modified such that a modified characteristic requests an increased engine torque (D) at least in a middle range (M) of an accelerator pedal position (P).

Description

The invention relates to a method and a device for adjusting the accelerator pedal characteristic in a motor vehicle.

In accelerator pedals or gas pedals, electronic systems are usually used to control an implementation of an acceleration request. These pedals control the torque request to the engine using an accelerator pedal characteristic that describes a relationship between the accelerator pedal position and the engine torque request of the driver.

Where appropriate, the term "engine torque" is used in the context of this document instead of the term "engine torque". Both terms are to be regarded as synonymous in the context of the present invention. The same applies to the terms "torque request" and "torque request".

From the DE 10 2004 061 263 B4 is a method for influencing the accelerator pedal behavior in a motor vehicle is known in which it is determined whether a dangerous driving dynamic situation for the vehicle exists, whereupon the pedal behavior of the accelerator pedal is affected. The driving-dynamics-dangerous situation is determined on the basis of sensor data from an environment sensor system or a navigation system. The change of the accelerator pedal characteristic is made in such a way that the characteristic is modified, which describes the relationship between the engine torque request of the driver and the accelerator pedal position. In order to take into account the dangerous driving dynamics situation, the engine torque request for the current accelerator pedal position is reduced, so that a lower engine torque is required than the accelerator pedal position compared to a regular driving situation.

Furthermore, it is known from practice that the accelerator characteristic is designed to be highly progressive. This means that the gradient of the accelerator characteristic increases with increasing accelerator pedal position and the accelerator characteristic, in particular in an initial range of the accelerator characteristic, for example at an accelerator pedal position of 0% to z. B. 20% of the maximum operable accelerator pedal position, runs relatively flat. This allows better maneuverability of the vehicle.

A disadvantage of this known determination of the accelerator characteristic is that in situations where a high starting torque is required due to a high driving resistance, z. B. on a slope or due to a heavy load of a commercial vehicle, the accelerator pedal must be strongly operated, but in this area the dosability of the instantaneous demand is very low due to the highly progressive map. This makes a controlled and safe starting process difficult.

It is therefore an object of the invention to provide an improved method for adjusting the accelerator pedal characteristic in a motor vehicle, with which disadvantages of conventional techniques can be avoided. The object of the invention is in particular to provide an improved method for adapting the accelerator pedal characteristic in a motor vehicle, with which an improved maneuverability of the vehicle is made possible. Another object is to provide a device for adjusting the accelerator pedal characteristic in a motor vehicle, with the disadvantages of conventional devices can be avoided.

These objects are achieved by a method having the features of the main claim and by a device having the features of the independent claim. Advantageous embodiments and applications of the invention are the subject matter of the dependent claims and are explained in more detail in the following description with partial reference to the figures.

The invention relates to a method for adapting the accelerator pedal characteristic in a motor vehicle, in which an accelerator pedal characteristic describing the relationship between accelerator pedal position and engine torque demand of the driver is modified. According to the method, it is determined whether there is a situation of increased running resistance. In the event that there is a situation of increased driving resistance, the accelerator characteristic is modified, such that a modified characteristic, at least in a central region of an accelerator pedal position requests an increased engine torque. By such a change in the accelerator pedal characteristic, for example in a control unit, a response of the accelerator pedal can be selectively changed, so that at an increased driving resistance the necessary starting torque is achieved even at a lower accelerator pedal value and thus the meterability is improved. By means of the modified accelerator characteristic, the accelerator pedal position or accelerator pedal position is accordingly reinterpreted and adapted to the increased driving resistance.

One possibility of the realization according to the invention provides here that a deviation of the modified characteristic from the original characteristic is higher in a central region of an accelerator pedal position than in an initial and an end region of the accelerator pedal position. This offers the advantage that on the one hand dangerously high Torques can be avoided with very small accelerator pedal values and on the other hand, the driving behavior in the end of the curve approximates the normal driving behavior.

It is particularly advantageous to set the modified characteristic such that in a central region of the accelerator characteristic an average slope of the modified characteristic is less than the slope of the original characteristic. As a result, a particularly good metering of the starting behavior of the vehicle with increased driving resistance can be made possible, so that a safe maneuvering in the slope and / or a start with heavy cargo is possible.

According to a further advantageous embodiment, an upper limit for the deviation of the modified characteristic from the original characteristic can be specified. Such an upper limit can serve as a safety limit to avoid dangerously high torque requirements.

According to a further variant of this embodiment, a curve of the modified characteristic curve can be defined while maintaining the upper limit, such that the deviation of the modified characteristic curve from the original characteristic curve as a function of a driving resistance or as a function of a variable influencing the driving resistance is at least in the middle range , For example, the vehicle mass and / or the road gradient, is set. A particular advantage of this embodiment is therefore that the course of the modified characteristic is dynamically adaptable to the height of the determined driving resistance, so that, for example, the course of the characteristic can be adjusted specifically to the current load condition of the vehicle and / or the current road gradient. At the same time, the upper limit ensures that the deviation from the original characteristic curve is within predefined safety limits.

According to a further variant, there is the possibility that a driving resistance is determined and, if the determined driving resistance exceeds a predetermined threshold, that the modified characteristic is set so that the driving resistance is only partially compensated by the modified characteristic. A complete, d. H. One hundred percent compensation would mean that the same accelerator pedal travel would be necessary for different driving resistances in order to achieve the necessary starting torque. However, if in situations of increased driving resistance only a partial compensation, for example, a compensation of 50% of the driving resistance made, this has the advantage that the driver is alerted by the at least partially changed response of the accelerator pedal to the presence of increased driving resistance and thus is caused to rank more attentively, which increases safety. As a result, an optimal compromise between better maneuverability due to the adaptation of the accelerator pedal characteristic and at the same time a driving behavior adapted to the driving situation with increased driving resistance of the driver can be promoted.

Further, it is possible to set the course of the modified characteristic such that the deviation from the original characteristic increases continuously or stepwise with increasing running resistance. For example, the modified characteristic may be increased proportionally with increase in the running resistance to provide a continuous family of characteristics. Alternatively, it is possible to assign a respective modified characteristic curve to predetermined driving resistance ranges, so that a plurality of mutually different accelerator pedal characteristics are used, one of which is selected as a function of the particular driving resistance. Furthermore, within the scope of the invention it is possible to determine a modified characteristic directly as a function of the vehicle mass and / or an increasing road gradient.

According to a further preferred embodiment, a deviation of the upper limit from the original characteristic in a central region of an accelerator pedal position is higher than in the starting and the end region of the accelerator pedal position. As a result, as already mentioned above, it can be ensured that dangerously high torque requirements can be avoided with very small accelerator pedal values. In the event of a fault, for example, if an incline is incorrectly detected, but the vehicle is in the plane, safe maneuverability can continue to be ensured in this way.

In the initial region of the accelerator pedal position, the upper limit can also be identical to the original characteristic, so that there is no adaptation of the accelerator characteristic in this area at all.

Further, in the initial region, the modified characteristic may be set so that, for a given accelerator pedal position, the increased engine torque according to the modified characteristic does not deviate more than 10% with respect to a maximum engine reference torque requestable by the accelerator pedal from the original engine torque according to the original characteristic. Thereby, a jerky start of the vehicle can be prevented in a wrong determination of the driving resistance.

Advantageously, the course of the modified characteristic curve in the middle region can be set to be substantially linear. Thereby, the response of the accelerator pedal is specifically changed so that a well-manageable and well manageable shunting behavior is made possible in a situation of increased driving resistance.

The middle range may be set to include at least a range of 40% to 60% of the accelerator pedal position. Further preferably, the central region may include at least a range of 35% to 65% of the accelerator pedal position. In the context of the invention, it has been found that particularly good maneuverability in situations of increased driving resistance can be made possible by the inventive adaptation of the accelerator pedal characteristic in these areas.

Further, the initial range may correspond to a range of 0% to at least 10% of the accelerator pedal position. Further preferably, the initial range may correspond to a range of 0% to at least 15% or a range of 0% to at least 20% of the accelerator pedal position.

The presence of a situation of increased driving resistance can be recognized from the fact that a calculated driving resistance is greater than a predetermined threshold value. The presence of a situation of increased driving resistance can be detected in particular as a function of a road gradient and / or of a vehicle mass.

The invention further relates to a device for adjusting the accelerator pedal characteristic in a motor vehicle, comprising detection means for detecting the presence of a situation increased driving resistance and accelerator pedal adjusting means, which are designed to modify in a situation of increased driving resistance of an accelerator pedal characteristic describing the relationship between accelerator pedal position and engine torque request of the driver in such a way that a modified characteristic line requests an increased engine torque at least in a middle region of an accelerator pedal position.

In order to avoid repetitions, features disclosed purely in accordance with the method should also be disclosed in accordance with the device and should be able to be claimed.

The invention further relates to a motor vehicle, preferably a commercial vehicle, with the device for adjusting the accelerator pedal characteristic in a motor vehicle.

The preferred embodiments and features of the invention described above can be combined with one another as desired. Further details and advantages of the invention will be described below with reference to the accompanying drawings.

1 illustrates the adaptation of the accelerator pedal characteristic in a motor vehicle, in particular in a commercial vehicle, according to an embodiment of the invention.

This shows 1 the course of a modified characteristic 2 compared to the original characteristic 1 , The characteristics 1 and 2 each determine the relationship between the accelerator pedal position or accelerator pedal position and the engine torque request of the driver. The characteristic 1 is an accelerator characteristic known from the prior art, which according to the invention continues to be used in situations not increased driving resistance for requesting the engine torque. In 1 is the highly progressive course of the accelerator characteristic 1 Visible, the slope gradually increases with increasing accelerator pedal position. The abscissa here shows the accelerator pedal position P as a percentage of the maximum possible accelerator pedal travel, where 0% corresponds to a non-actuated accelerator pedal and 100% correspond to a fully worn accelerator pedal. The ordinate indicates the engine torque request of the driver as a percentage of engine reference torque D. The engine reference torque is the maximum engine torque that can be achieved by the engine. As in 1 It can be seen, it is common in commercial vehicles that already at 90% of the accelerator pedal travel, so not fully depressed accelerator pedal, 100% of the engine reference torque D are required because the fully depressed position for the so-called kick-down function is used.

Furthermore, in 1 a start region A, a middle region M and an end region of the accelerator pedal position are indicated. In the present embodiment, the initial range includes 0% to 20% of the accelerator pedal travel, the midrange 35% to about 65% of the accelerator pedal travel, and the end portion the remaining range of the accelerator pedal travel to 90%. It is emphasized that the aforementioned percentages are to be regarded as exemplary only and the determination of the ranges for different applications can also be defined differently.

In situations in which there is no increased driving resistance, for example when driving in the plane or in an unloaded vehicle, the original characteristic 1 used for the control of the engine torque.

However, if the vehicle control recognizes a situation of increased driving resistance, the original characteristic curve becomes dependent on the determined driving resistance 1 modified and the modified characteristic 2 based on the control of the engine torque. Out 1 it can be seen that the modified characteristic 2 each request a higher engine torque at the same accelerator pedal position, the deviation from the original characteristic in the middle region M is greatest. This is indicated by the vertical dashed arrows representing the deviation of the modified characteristic 2 from the original characteristic 1 mark.

In the initial area A is the possible deviation of the modified characteristic 2 from the original characteristic 1 very low, with the corresponding sections of these characteristics in the initial area with the reference numerals 2_A and 1_A Marked are. It has already been mentioned above, that this can be ensured that in case of error, z. B. in a false detection of a slope, but the vehicle is actually in a plane, yet a safe start in the plane can be made, as a dangerous for this situation torque request is avoided.

In 1 is further with the line 3 an upper limit is indicated for the deviation of the modified characteristic curve 2 is given by the original characteristic curve, that of the modified characteristic curve 2 always be respected. In other words, the deviation of the modified characteristic may 2 maximum deviation of the upper limit 3 correspond. In 1 is only a single modified characteristic 2 shown, however, it is within the scope of the invention, the possibility, depending on the particular driving resistance, the modified characteristic 2 in the range between the original characteristic 1 and the upper limit 3 to vary, so that with increasing resistance each shifted upwards modified characteristics 2 be determined.

In 1 It is further shown that the modified characteristic in the central region has a substantial linear course 2_m which allows good and even maneuverability in situations of increased road resistance. Through the horizontal arrow 4 is clarified that for the same resulting moment a much smaller accelerator pedal value based on the modified characteristic 2 in comparison to the original characteristic 1 is needed, so that a maneuvering in the slope for the driver comes close to a maneuvering in the plane, as more accelerator pedal path for dosing is available. This is made possible in particular by the fact that the slope of the middle section 2_m the modified characteristic has a lower slope than the comparable middle range 1_m the original characteristic in this area M.

The presence of a situation of increased driving resistance can be detected when a calculated running resistance is greater than a predetermined threshold for the driving resistance. The calculation of the driving resistance is known from the prior art and a size that is usually present in the known control devices of commercial vehicles and is determined by a vehicle model, with the driving resistance relevant variables such as air resistance, rolling resistance, the pitch resistance and the acceleration resistance can be calculated or estimated. Quantities such as the road gradient are calculated, for example, by means of an acceleration sensor, the vehicle mass can be estimated from an engine torque and from the resulting vehicle acceleration.

Although the invention has been described with reference to particular embodiments, it will be apparent to those skilled in the art that various changes may be made and equivalents may be substituted for without departing from the scope of the invention. In addition, many modifications can be made without leaving the associated area. Accordingly, the invention should not be limited to the disclosed embodiments, but the invention is intended to embrace all embodiments which fall within the scope of the appended claims.

LIST OF REFERENCE NUMBERS

1

Original characteristic

1_A

Initial range of the original characteristic

1_m

Middle range of the original characteristic

2

Modified characteristic

2_A

Initial range of the modified characteristic

2_m

Middle range of the modified characteristic

3

Upper limit

4

Reduced accelerator pedal travel

A

initial region

M

Middle area

e

end

D

engine torque

P

Accelerator pedal position

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102004061263 B4 [0004]

Claims (13)

Method for adapting the accelerator pedal characteristic in a motor vehicle, in which an accelerator characteristic curve describing the relationship between the accelerator pedal position and the engine torque request of the driver ( 1 ) is modified, characterized in that it is determined whether a situation of increased driving resistance is present; and in the event that there is an increased driving resistance situation, the accelerator characteristic ( 1 ), such that a modified characteristic ( 2 ) requests an increased engine torque (D) at least in a middle region (M) of an accelerator pedal position (P). Method according to Claim 1, characterized in that a deviation of the modified characteristic ( 2 ) from the original characteristic ( 1 ) is higher in a middle region (M) of an accelerator pedal position (P) than in an initial (A) and an end region (E) of the accelerator pedal position. A method according to claim 1 or 2, characterized in that in a central region (M) of the accelerator characteristic an average slope of the modified characteristic ( 2 ) is less than the slope of the original characteristic ( 1 ). Method according to one of the preceding claims, characterized in that (a) an upper limit ( 3 ) for the deviation of the modified characteristic ( 2 ) from the original characteristic ( 1 ) is given; and (b) that a curve of the modified characteristic ( 2 ) in compliance with the upper limit ( 3 ), such that at least in the middle region (M) the deviation of the modified characteristic ( 2 ) from the original characteristic ( 1 ) is determined as a function of a driving resistance or as a function of a variable influencing the driving resistance, for example the vehicle mass and / or the road gradient. A method according to claim 4, characterized in that a driving resistance is determined and, if the determined driving resistance exceeds a predetermined threshold, that the modified characteristic ( 2 ) is set so that the driving resistance through the modified characteristic ( 2 ) is only partially compensated. A method according to claim 4 or 5, characterized in that the course of the modified characteristic ( 2 ) is set so that the deviation from the original characteristic increases continuously or stepwise with increasing running resistance. Method according to one of claims 3 to 6, characterized in that (a) that a deviation of the upper limit ( 3 ) from the original characteristic ( 1 ) in a middle region (M) of an accelerator pedal position (P) is higher than in the beginning (A) and the end region (E) of the accelerator pedal position (P); and / or (b) that the upper limit ( 3 ) in the initial region (A) of the accelerator pedal position (P) identical to the original characteristic ( 1 ) or for a given accelerator pedal position the increased engine torque (D) according to the modified characteristic ( 2 ) not more than 10% with respect to a maximum engine reference torque requestable by the accelerator pedal from the original engine torque according to the original characteristic ( 1 ) deviates. Method according to one of the preceding claims, characterized in that the course of the modified characteristic ( 2 ) in the central region (M) is substantially linear. Method according to one of the preceding claims, characterized in that (a) that the central region (M) contains at least a range of 40% to 60% of the accelerator pedal position (P); and / or (b) that the central region (M) includes at least a range of 35% to 65% of the accelerator pedal position (P). Method according to one of the preceding claims, characterized in that (a) that the initial range (A) corresponds to a range of 0% to at least 10% of the accelerator pedal position (P); and / or (b) that the initial range (A) corresponds to a range of 0% to at least 15% of the accelerator pedal position (P). Method according to one of the preceding claims, characterized in that (a) the presence of a situation of increased driving resistance is detected when a calculated driving resistance is greater than a predetermined threshold value; and / or (b) that the presence of a situation of increased road resistance is detected as a function of a road gradient and / or of a vehicle mass. Device for adapting the accelerator pedal characteristic in a motor vehicle, comprising detection means for detecting the presence of a situation of increased driving resistance; and accelerator pedal adjusting means, which are designed to modify an accelerator pedal characteristic describing the relationship between accelerator pedal position and engine torque demand of the driver in the presence of a situation of increased driving resistance, such that a modified characteristic ( 2 ) requests an increased engine torque (D) at least in a middle region (M) of an accelerator pedal position (P). Motor vehicle, preferably utility vehicle, with a device according to claim 12.

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